Bleaching powder [Ca(OCl)2], a new option for management of stem rot of Jute (Corchorus olitorius L. and C. capsularis L.) caused by Macrophomina phaseolina (Tassi) Goid

Abstract

To search for an alternative option against stem rot of jute (Corchorus olitorius L. and C. capsularis L.) caused by Macrophomina phaseolina (Tassi) Goid., experiment was carried out using bleaching powder or calcium hypochlorite [Ca(OCl)2]. In field experiment, bleaching powder were applied as soil application at different doses @ 5-150 kg/ha and sowing was done with normal NPK fertilizers after gestation period of 2-15 days in randomized block design with three replications on a new jute variety, JRO 8432 at main farm of CRIJAF, Nilganj, Barrackpore, India, during normal cropping season of 2012-13. The radial growth of M. phaseolina was completely checked in food poisoning technique in vitro at 5000 ìg/ml of bleaching powder both at 24 and 48 hours after incubation. At lower dose growth inhibition decreased. At 100 and 1000 ìg/ml, 87.3, 93.3% and 93.6, 96.6 inhibitions were observed after 24 and 48 hours, respectively. During further incubation of 24 hrs at a concentration of 5000 ìg/ml of bleaching powder, no fresh growth was observed indicating inhibition of M. phaseolina completely. In the experimental field, out of all the doses of bleaching powder, soil application @ 30 kg/ha 7 days ahead of sowing was found best against jute stem rot with highest dry fibre yield compared to check (with no soil application) and higher (50-150 kg/ha) and lower (5-20 kg/ha) doses in all the four dates (30-120 DAS) of observations. It restricted stem rot of jute to 2.1 and 6% as compared to 15.1 and 24% in untreated check at 90-120 DAS, respectively. As the dose of soil application of bleaching powder increased from @ 5-120 kg/ha, the jute stem rot decreased slowly reaching minimum at 30 kg/ha indicating that this dose being most effective against jute stem rot.